These answers are just what you’d expect, because they correspond to many leading churches in modern evangelicalism that combine nominally traditional doctrine with shallow commitment and have been plagued by rampant divorce and extramarital sex—all against a backdrop of extreme cultural hostility. In other words, we’re about 95 percent like the surrounding culture and hated for the 5 percent deviation.

But one religious group shows consistent growth year by year and decade by decade. Mormons, living in the same country and culture as evangelicals, keep growing their church. Why? I propose six reasons.

1. Mormons have bigger families.

This is the easiest and simplest explanation. But it’s far from the entire story. In fact, if family size were determinative, then many churches in America would be growing at a rate that exceeded general population growth. After all, the birth rate of religious families generally exceeds that of nonreligious families. Instead, church after church shrinks or remains basically steady in spite of the higher birth rate. Mormons start with a bigger baseline family, but then they tend to hold on to their kids while evangelicals often do not.

2. Mormons have lower divorce rates.

While regular church-going evangelicals divorce less often than secular couples, Mormon-marrying Mormons have the lowest divorce rate of any major religious group. Families that stay together are more likely to pray together. Few experiences are more demoralizing to a young Christian than seeing his parents destroy their own marriage and destroy their own kids’ childhoods in a blaze of selfishness, lust, and pride.

3. Mormons share their faith.

Who hasn’t met a Mormon missionary? My wife used to debate them at the doorstep, but we made many new Mormon friends and now welcome them into our home, offer them rides in the rain, and generally get to know young people who experience a very different young adult rite of passage than your typical evangelical. A Mormon mission is a sacrifice—a deep sacrifice. Evangelism not only wins converts, it also strengthens the faith of the evangelist.

4. Mormons are “orthodox.”

No evangelical can call Mormons “orthodox” in terms of the Apostles’ Creed and biblical canon. But they are orthodox within their own, distinct faith tradition. In other words, members of a Mormon church tend to know and believe their faith. Go to a typical evangelical church—like my own Presbyterian congregation—and you’ll find very wide theological divergence. Nationally, 84 million people self-report as evangelicals, but of that number only 19 million according to Barna actually have orthodox evangelical beliefs. In other words, the evangelical church must improve in transmitting even the most basic elements of the Christian faith from generation to generation.

5. Mormon leaders ask a lot of their members.

I’m always amazed at the level of church involvement of Mormons compared to evangelicals. From giving, to service, to teaching, to raw number of hours in the church building, Mormons are simply doing more. To some evangelical critics, you’d think we lose members because we’re so demanding. But compared to the Mormon experience, evangelical churches are a carnival ride of short services, low accountability, and rare church discipline. If you’re a faithful Mormon, you’re not living a 95 percent secular life like so many evangelicals. At least in this regard, Mormons are truly countercultural.

6. Mormons are less selfish.

Add up points one through five, and you get to the sum. Too many of us evangelicals have forgotten the fundamental paradox of Scripture—you won’t gain your life until you lose your life. We ask our kids to lose just a little life to gain . . . what, exactly? If Christianity isn’t worth losing everything, is it worth only losing some things? And if it’s not worth losing everything, why is it worth losing anything?

Big families, intact families, years-long missions, faithfulness to church teaching, and a lifetime of service add up to a sustainable, Christ-honoring counterculture. By contrast many of our churches will prove to be ashes and dust—unable to resist a culture that relentlessly demonizes even the small remaining differences between evangelicals and atheists.

As a Calvinist member of the Presbyterian Church in America, I’ve got my theological differences with the LDS church. But if we evangelicals don’t believe we have anything to learn from our Mormon friends, then we’re foolish. Our churches will not grow by conforming, by shedding the last remaining distinctions between Christians and the secular world. That route is well-traveled by the imploding mainline denominations. Instead of asking less of our families and youth, let’s ask more by the grace of God and the power of the Spirit. Instead of giving less, let’s give more. Instead of believing we’re unique theological snowflakes capable of discerning truth on our own, let’s teach church doctrine early and well. And let’s not be afraid of church discipline.

What are the core lessons for the church? Conform and die. Resist and live.”